Acoustical Holography — A Comparison with Phased Array Sonar
The primary difference between phased-array sonar and acoustical holography lies only in the order in which the temporal and spatial processing operations are carried out. It is shown that this difference indirectly leads to an advantage for holography in terms of either signal-tonoise performance or reduced processing complexity in many types of application. The holographic approach has an important signal-to-noise advantage over scanned phasedarray systems because of parallel processing. Compared with multibeam sonar, the holographic spatial processing of data obtained from uniform arrays can be carried out with fewer operations than phased-array parallel beam-forming via adders and tapped shift registers because of the CooleyTukey algorithm. A significant reduction in processing operations due to data reduction in holography, especially for active systems, is also possible.
KeywordsSpatial Processing DIMUS System Uniform Array Object Field Holographic System
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